While they were each once hailed as the lightest solid material ever made, metallic microlattice and aerogel have now been moved back to second and third place (respectively), with aerographite taking the crown. Developed by a team from the Technical University of Hamburg and Germany’s University of Kiel, the material is composed of 99.99 percent air, along with a three-dimensional network of porous carbon nanotubes that were grown into each other.